Part of the charter would require Russia to effectively allow third-party access to the state-owned Gazprom's export pipeline network.

Europe currently relies on Russia for a quarter of its natural gas. Gazprom officials have threatened to sell the gas elsewhere if European countries move to limit the company's expansion.

Earlier this year, Gazprom temporarily cut gas supplies to Ukraine in a price dispute. The blockage sharply reduced deliveries to other European countries, prompting calls from some EU members for applying the bloc's anti-monopoly rules to the Russian firm.